Display device

ABSTRACT

A display device including a base layer, a pixel circuit layer disposed on the base layer and including a pixel circuit and a plurality of insulation layers, a first electrode electrically connected to the pixel circuit, a second electrode spaced apart from the first electrode, a light emitting element electrically connected to the first electrode and the second electrode, a first refraction layer disposed on the pixel circuit layer and having a first refractive index, and a second refraction layer disposed on the light emitting element and having a second refractive index larger than the first refractive index.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2018-0117271, filed on Oct. 2, 2018, which is herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND Field

Exemplary embodiments of the invention relate to a display device havingimproved emission efficiency.

Discussion of the Background

A display device may include a light emitting element. The lightemitting element may be electrically connected to an electrode and emitlight according to a voltage applied to the electrode. The lightemitting element may be directly disposed on the electrode, or aseparate light emitting element may be transferred onto the electrode.The light emitting element may emit light. The light emitted from thelight emitting element may be emitted to the outside of a display panel.When the light emitted to the outside of the display panel is reduced inemission efficiency, luminance of the display panel may be deteriorated,or power for driving the display panel may increase.

The above information disclosed in this Background section is only forunderstanding of the background of the inventive concepts, and,therefore, it may contain information that does not constitute priorart.

SUMMARY

Exemplary embodiments of the present invention provide a display devicehaving improved emission efficiency.

Additional features of the inventive concepts will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the inventive concepts.

An exemplary embodiment of the inventive concept provides a displaydevice including: a base layer including a first area and a second areaadjacent to the first area; a pixel circuit layer disposed on the baselayer and including a pixel circuit and a plurality of insulationlayers; a first electrode electrically connected to the pixel circuit; asecond electrode spaced apart from the first electrode and disposed onthe same layer as the first electrode; a light emitting elementelectrically connected to the first electrode and the second electrode;a first refraction layer disposed on the pixel circuit layer and havinga first refractive index; and a second refraction layer disposed on thelight emitting element and having a second refractive index greater thanthe first refractive index. The first area overlaps the light emittingelement and the second refraction layer, and the second area overlapsthe first refraction layer.

The light emitting element may include a micro light emitting diodeelement.

The display device may further include an encapsulation layer coveringthe light emitting element and the pixel circuit.

The first refraction layer and the second refraction layer may bedisposed on the encapsulation layer, the first refraction layer may bedisposed to surround the first area on a plane, and the secondrefraction layer may overlap the first area and the second area.

The display device may further include a light blocking layer disposedon the encapsulation layer to overlap the pixel circuit.

The light blocking layer and the first refraction layer may be disposedadjacent to each other and covered by the second refraction layer.

The first refraction layer may be disposed on the light blocking layerto cover the light blocking layer.

The display device may further include a color filter layer overlappingthe first area and disposed between the encapsulation layer and thesecond refraction layer.

The display device may further include: a light blocking layer disposedon the second refraction layer to overlap the pixel circuit; and aplanarization layer disposed on the second refraction layer to cover thelight blocking layer and provide a planarization surface.

The display device may further include: a light blocking layer disposedon the second refraction layer to overlap the pixel circuit; and a colorfilter layer disposed on the second refraction layer and overlapping thefirst area.

The display device may further include a pattern layer disposed belowthe encapsulation layer, configured to cover the light emitting element,and having a third refractive index. The encapsulation layer has afourth refractive index that may be less than the third refractiveindex.

The display device may further include: a light blocking layer disposedon the second refraction layer to overlap the pixel circuit; and a colorfilter disposed on the second refraction layer to overlap the lightemitting element.

The display device may further include: a color filter disposed betweenthe encapsulation layer and the second refraction layer to overlap thelight emitting element; a light blocking layer disposed on the secondrefraction layer to overlap the pixel circuit; and a planarization layerconfigured to cover the light blocking layer and provide a planarizationsurface.

The display device may further include: a light blocking layer disposedon the encapsulation layer to overlap the pixel circuit; a color filterlayer disposed on the encapsulation layer to overlap the light emittingelement; and a planarization layer covering the light blocking layer andthe color filter layer. The first refraction layer and the secondrefraction layer may be disposed on the planarization layer.

The second refraction layer may cover the light emitting element, andthe first refraction layer may be disposed on the second refractionlayer and the pixel circuit layer to cover the second refraction layer.

The outermost surface of the second refraction layer may contact thefirst refraction layer and has a predetermined curvature.

The display device may further include a light blocking layer, whichdoes not overlap the light emitting element. The light blocking layermay be disposed between the first refraction layer and the pixel circuitlayer.

The display device may further include: a color filter layer disposed onthe first refraction layer to overlap the light emitting element; and aplanarization layer disposed on the first refraction layer to cover thecolor filter layer.

The display device may further include: a light blocking layer whichdoes not overlap the light emitting element and is disposed on the firstrefraction layer; a color filter layer disposed on the first refractionlayer to overlap the light emitting element; and a planarization layerdisposed on the first refraction layer to cover the color filter layer.

A groove may be defined in the pixel circuit layer by an inclined partincluding an end of each of the plurality of insulation layers, and thelight emitting element may be disposed in the groove.

The inclined part may be covered by the first electrode and the secondelectrode, and each of the first electrode and the second electrode mayinclude a reflective material.

The groove may have a depth greater than a thickness of the lightemitting element.

Another exemplary embodiment of the inventive concept provides a displaydevice including: a base layer; a pixel circuit layer disposed on thebase layer and including a transistor and insulation layers, each ofinsulation layers having a groove; a first electrode electricallyconnected to the transistor; a second electrode spaced apart from thefirst electrode and configured to receive a power source voltage; alight emitting element electrically connected to the first electrode andthe second electrode and disposed in the groove; a first refractionlayer overlapping an area adjacent to an emission area on which thelight emitting element is disposed and having a first refractive index;and a second refraction layer overlapping the emission area and having asecond refractive index greater than the first refractive index.

The first refraction layer may be disposed on the pixel circuit layer,and the second refraction layer may be disposed on the first refractionlayer to cover the first refraction layer and provide a planarizationsurface.

The second refraction layer may be disposed on the light emittingelement, and the first refraction layer may be disposed on the secondrefraction layer to cover the second refraction layer and provide aplanarization surface.

The groove may be defined by an inclined part including an end of eachof the insulation layers, the first electrode may cover one portion ofthe inclined part, the second electrode may cover the other portion ofthe inclined part, and each of the first electrode and the secondelectrode may include a reflective material.

The groove may have a depth greater than a thickness of the lightemitting element.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of theinvention, and together with the description serve to explain theinventive concepts.

FIG. 1 is a perspective view of a display device according to anexemplary embodiment of the inventive concept.

FIG. 2 is a block diagram of the display device according to anexemplary embodiment of the inventive concept.

FIG. 3 is an equivalent circuit diagram of a pixel according to anexemplary embodiment of the inventive concept.

FIG. 4 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 5 is an enlarged plan view illustrating a portion of constituentsof the display device according to an exemplary embodiment of theinventive concept.

FIG. 6A is an enlarged plan view illustrating a portion of theconstituents of the display device according to an exemplary embodimentof the inventive concept.

FIG. 6B is an enlarged plan view illustrating a portion of theconstituents of the display device according to an exemplary embodimentof the inventive concept.

FIG. 7A is an enlarged cross-sectional view illustrating a portion ofthe display device according to an exemplary embodiment of the inventiveconcept.

FIG. 7B is an enlarged cross-sectional view illustrating a portion ofthe display device according to an exemplary embodiment of the inventiveconcept.

FIG. 7C is an enlarged cross-sectional view illustrating a portion ofthe display device according to an exemplary embodiment of the inventiveconcept.

FIG. 7D is an enlarged cross-sectional view illustrating a portion ofthe display device according to an exemplary embodiment of the inventiveconcept.

FIG. 8 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 9 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 10 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 11 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 12 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 13 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 14 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 15 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 16 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 17 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 18 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

FIG. 19 is an enlarged cross-sectional view illustrating a portion ofthe display device according to an exemplary embodiment of the inventiveconcept.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various exemplary embodiments of the invention. As usedherein “embodiments” are non-limiting examples of devices or methodsemploying one or more of the inventive concepts disclosed herein. It isapparent, however, that various exemplary embodiments may be practicedwithout these specific details or with one or more equivalentarrangements. In other instances, well-known structures and devices areshown in block diagram form in order to avoid unnecessarily obscuringvarious exemplary embodiments. Further, various exemplary embodimentsmay be different, but do not have to be exclusive. For example, specificshapes, configurations, and characteristics of an exemplary embodimentmay be used or implemented in another exemplary embodiment withoutdeparting from the inventive concepts.

Unless otherwise specified, the illustrated exemplary embodiments are tobe understood as providing exemplary features of varying detail of someways in which the inventive concepts may be implemented in practice.Therefore, unless otherwise specified, the features, components,modules, layers, films, panels, regions, and/or aspects, etc.(hereinafter individually or collectively referred to as “elements”), ofthe various embodiments may be otherwise combined, separated,interchanged, and/or rearranged without departing from the inventiveconcepts.

The use of cross-hatching and/or shading in the accompanying drawings isgenerally provided to clarify boundaries between adjacent elements. Assuch, neither the presence nor the absence of cross-hatching or shadingconveys or indicates any preference or requirement for particularmaterials, material properties, dimensions, proportions, commonalitiesbetween illustrated elements, and/or any other characteristic,attribute, property, etc., of the elements, unless specified. Further,in the accompanying drawings, the size and relative sizes of elementsmay be exaggerated for clarity and/or descriptive purposes. When anexemplary embodiment may be implemented differently, a specific processorder may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order. Also, like reference numerals denote like elements.

When an element, such as a layer, is referred to as being “on,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, connected to, or coupled to the other element or layer orintervening elements or layers may be present. When, however, an elementor layer is referred to as being “directly on,” “directly connected to,”or “directly coupled to” another element or layer, there are nointervening elements or layers present. To this end, the term“connected” may refer to physical, electrical, and/or fluid connection,with or without intervening elements. Further, the D1-axis, the D2-axis,and the D3-axis are not limited to three axes of a rectangularcoordinate system, such as the x, y, and z—axes, and may be interpretedin a broader sense. For example, the D1-axis, the D2-axis, and theD3-axis may be perpendicular to one another, or may represent differentdirections that are not perpendicular to one another. For the purposesof this disclosure, “at least one of X, Y, and Z” and “at least oneselected from the group consisting of X, Y, and Z” may be construed as Xonly, Y only, Z only, or any combination of two or more of X, Y, and Z,such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

Although the terms “first,” “second,” etc. may be used herein todescribe various types of elements, these elements should not be limitedby these terms. These terms are used to distinguish one element fromanother element. Thus, a first element discussed below could be termed asecond element without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath,” “below,” “under,” “lower,”“above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), andthe like, may be used herein for descriptive purposes, and, thereby, todescribe one elements relationship to another element(s) as illustratedin the drawings. Spatially relative terms are intended to encompassdifferent orientations of an apparatus in use, operation, and/ormanufacture in addition to the orientation depicted in the drawings. Forexample, if the apparatus in the drawings is turned over, elementsdescribed as “below” or “beneath” other elements or features would thenbe oriented “above” the other elements or features. Thus, the exemplaryterm “below” can encompass both an orientation of above and below.Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90degrees or at other orientations), and, as such, the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof. It is also noted that, as used herein, the terms“substantially,” “about,” and other similar terms, are used as terms ofapproximation and not as terms of degree, and, as such, are utilized toaccount for inherent deviations in measured, calculated, and/or providedvalues that would be recognized by one of ordinary skill in the art.

Various exemplary embodiments are described herein with reference tosectional and/or exploded illustrations that are schematic illustrationsof idealized exemplary embodiments and/or intermediate structures. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments disclosed herein should notnecessarily be construed as limited to the particular illustrated shapesof regions, but are to include deviations in shapes that result from,for instance, manufacturing. In this manner, regions illustrated in thedrawings may be schematic in nature and the shapes of these regions maynot reflect actual shapes of regions of a device and, as such, are notnecessarily intended to be limiting.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure is a part. Terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and should not be interpreted in anidealized or overly formal sense, unless expressly so defined herein.

Hereinafter, exemplary embodiments of the inventive concept will bedescribed with reference to the accompanying drawings.

FIG. 1 is a perspective view of a display device DD according to anexemplary embodiment of the inventive concept.

Referring to FIG. 1, the display device DD may display an image througha display area DA. FIG. 1 illustrates an example in which the displayarea DA is provided on a surface defined by a first direction DR1 and asecond direction DR2 crossing the first direction DR1. However, adisplay area of a display device according to another exemplaryembodiment of the inventive concept may be provided on a curved surface.

A thickness of the display device DD is indicated in a third directionDR3. The directions indicated as the first to third direction DR1, DR2,and DR3 may be a relative concept and thus changed into differentdirections. In this specification, “when viewed in a plane view” maymean a view in the third direction DR3. Also, the “thickness direction”may mean the third direction DR3.

FIG. 1 illustrates an example in which the display device DD is atelevision. However, the display device DD may be applied to largeelectronic devices such as a monitor, or an external billboard as wellas small and middle electronic devices such as a personal computer, apersonal computer, a notebook computer, a personal digital terminal, acar navigation unit, a game console, a smart phone, a tablet, and acamera. Also, the above-described devices are merely examples of theinventive concept, and thus, the display device DD may be adopted forother electronic equipment unless departing from the spirit and scope ofthe invention.

FIG. 2 is a block diagram of the display device according to anexemplary embodiment of the inventive concept.

Referring to FIG. 2, the display device DD may include a display panelDP, a signal controller TC (or a timing controller), a data driver DDV,and a scan driver GDV. Each of the signal controller TC, the data driverDDV, and the scan driver GDV may include a circuit.

The display panel DP may be a micro light emitting element display panelDP including a micro light emitting element. For example, the displaypanel DP may be a micro LED display panel DP.

The display panel DP may include a plurality of data lines DL1 to DLm, aplurality of scan lines SL1 to SLn, and a plurality of pixels PX.

The plurality of data lines DL1 to DLm may extend in the first directionDR1 and be arranged in the second direction DR2 crossing the firstdirection DR1. The plurality of scan lines SL1 to SLn may extend in thesecond direction DR2 and be arranged in the first direction DR1.

Each of the pixels PX may include a light emitting element ED (see FIG.3) and a pixel circuit PXC (see FIG. 3) electrically connected to thelight emitting element ED. The pixel circuit PXC (see FIG. 3) mayinclude a plurality of transistors TR1 and TR2 (see FIG. 3). A firstpower source voltage ELVDD and a second power source voltage ELVSS maybe provided to each of the pixels PX.

The pixels PX may be arranged in a regular rule on the plane of thedisplay panel DP. Each of the pixels PX may display one of primarycolors or one of mixed colors. The primary colors may include red,green, and blue colors, and the mixed colors may include various colorssuch as yellow, cyan, magenta, and white colors. However, the inventiveconcept is not limited to the colors displayed by the pixels PX.

The signal controller TC receives image data RGB provided from theoutside. The signal controller TC may convert the image data RGB tomatch an operation of the display panel DP and thereby to generateconverted image data R′G′B′ and output the converted image data R′G′B′to the data driver DDV.

Also, the signal controller TC may receive a control signal CS providedfrom the outside. The control signal CS may include a verticalsynchronization signal, a horizontal synchronization signal, a mainclock signal, a data enable signal, and the like.

The signal controller TC provides a first control signal CONT1 to thedata driver DDV and provides a second control signal CONT2 to the scandriver GDV. The first control signal CONT1 may be a signal forcontrolling the data driver DDV, and the second control signal CONT2 maybe a signal for controlling the scan driver GDV.

The data driver DDV may provide an electrical signal to the plurality ofdata lines DL1 to DLm in response to the first control signal CONT1received from the signal controller TC. The data driver DDV may berealized as an independent integrated circuit and thus, may beelectrically connected to one side of the display panel DP or directlymounted on the display panel DP. Also, the data driver DDV may berealized as either a single chip or a plurality of chips.

The scan driver GDV may provide an electrical signal to the plurality ofscan lines SL1 to SLn in response to the second control signal CONT2received from the signal controller TC. The scan driver GDV may beintegrated with a predetermined area of the display panel DP. Forexample, the scan driver GDV may include a plurality of transistorsformed through the same process as the pixel circuit PXC (see FIG. 3) ofthe pixels PX, for example, a low temperature polycrystalline silicon(LTPS) process or a low temperature polycrystalline oxide (LTPO)process. Also, the scan driver GDV according to another exemplaryembodiment of the inventive concept may be realized as an independentintegrated circuit chip and electrically connected to one side of thedisplay panel DP.

While a gate turn-on voltage is applied to one scan line of theplurality of scan lines SL1 to SLn, a switching transistor of each ofthe pixels, which are arranged in one row and connected to the one scanline, may be turned on. Here, the data driver DDV provides data drivingsignals to the data lines DL1 to DLm. The data driving signals suppliedto the data lines DL1 to DLm are applied to the corresponding pixelsthrough the turned-on switching transistor. The data driving signals areanalog voltages corresponding to gray level values of the image data.

FIG. 3 is an equivalent circuit diagram of the pixel according to anexemplary embodiment of the inventive concept. FIG. 3 illustrates anequivalent circuit diagram of one pixel PX (hereinafter, referred to apixel) of the plurality of pixels PX.

Referring to FIG. 3, the pixel PX may be electrically connected to aplurality of signal lines. In this exemplary embodiment, a scan line SL,a data line DL, a first power source line PL1, and a second power sourceline PL2 of the signal lines are illustrated as an example. However,this is merely an example. For example, the pixel PX according to theinventive concept may be additionally connected to various signal lines,but is not limited to a specific embodiment.

The pixel PX may include the light emitting element ED and the pixelcircuit PXC. The pixel circuit PXC may include a first transistor TR1, acapacitor CAP, and a second transistor TR2. This is merely an example.That is, the number of transistors and the number of capacitors providedin the pixel circuit PXC are not limited to that shown in FIG. 3. Forexample, the pixel circuit PXC according to another exemplary embodimentof the inventive concept may include seven transistors and onecapacitor.

The first transistor TR1 may be a switching transistor that controlsturn-on/off of the pixel PX. The first transistor TR1 may transmit orblock the data signal transmitted through the data line DL in responseto the scan signal transmitted through the scan line SL.

The capacitor CAP is connected to the first transistor TR1 and the firstpower source line PL1. The capacitor CAP charges electrical charges byan amount corresponding to a difference between the data signal receivedfrom the first transistor TR1 and a first power source voltage ELVDDapplied to the first power source line PL1.

The second transistor TR2 is connected to the first transistor TR1, thecapacitor CAP, and the light emitting element ED. The second transistorTR2 controls driving current flowing through the light emitting elementED to correspond to a charge amount stored in the capacitor CAP. Aturn-on time of the second transistor TR2 may be determined according tothe amount of charge stored in the capacitor CAP.

Each of the first transistor TR1 and the second transistor TR2 may be anN-type transistor or a P-type transistor. Also, according to anotherexemplary embodiment of the inventive concept, one of the firsttransistor TR1 and the second transistor TR2 may be an N-typetransistor, and the other may be a P-type transistor.

The light emitting element ED may be electrically connected to thesecond transistor TR2 and the second power source line PL2. The lightemitting element ED may receive the second power source voltage EVLSSthrough the second power source line PL2.

The light emitting element ED emits light at a voltage corresponding toa difference between the signal transmitted through the secondtransistor TR2 and the second power source voltage ELVSS receivedthrough the second power source line PL2.

The light emitting element ED may be a micro light emitting diodeelement. The micro light emitting diode element may be an LED elementhaving a length of several nanometers to several hundred micrometers.However, the length of the micro light emitting diode element is merelyan example. For example, the length of the micro light emitting diodeelement is not limited to the above-described length range.

The light emitting element ED may emit having a specific wavelengthband. For example, the light emitting element ED may emit red light,blue light, or green light.

The light emitting element ED may include an n-type semiconductor layer,a p-type semiconductor layer, and an active layer. The active layer maybe disposed between the n-type semiconductor layer and the p-typesemiconductor layer.

The n-type semiconductor layer may be provided by doping an n-typedopant into a semiconductor layer, and the p-type semiconductor layermay be provided by doping a p-type dopant into the semiconductor layer.The semiconductor layer may include a semiconductor material. Forexample, the semiconductor material may be GaN, AlN, AlGaN, InGaN, InN,InAlGaN, or AlInN, but is not limited thereto. The n-type dopant maysilicon (Si), germanium (Ge), tin (Sn), selenium (Se), tellurium (Te),or a combination thereof, but is not limited thereto. The p-type dopantmay be magnesium (Mg), zinc (Zn), calcium (Ca), strontium (Sr), barium(Ba), or a combination thereof, but is not limited thereto.

The active layer may have at least one of a single quantum wellstructure, a multi quantum well structure, a quantum wire structure, ora quantum dot structure. The active layer may be a region in whichelectrons injected through the n-type semiconductor layer and holesinjected through the p-type semiconductor layer are recombined with eachother. The active layer may be a layer that emits light having energydetermined by the energy band inherent to the material. The active layermay be disposed at various positions according to the kinds of diodesused.

Although one light emitting element ED is connected between the secondtransistor TR2 and the second power source line PL2 in FIG. 3, aplurality of light emitting elements ED may be provided. The pluralityof light emitting elements ED may be connected in parallel with eachother.

FIG. 4 is a cross-sectional view of the display panel according to anexemplary embodiment of the inventive concept.

Referring to FIGS. 3 and 4, the display panel DP may include a baselayer BL, a pixel circuit layer PXCL, a first electrode E1, a secondelectrode E2, a light emitting element ED, an encapsulation layer ECL, afirst refraction layer CL1, a second refraction layer CL2, and a lightblocking layer BM.

The base layer BL may include a flexible material. For example, the baselayer BL may be a plastic substrate. The plastic substrate may includeat least one of an acrylic-based resin, a methacrylic-based resin, apolyisoprene-based resin, a vinyl-based resin, an epoxy-based resin, aurethane-based resin, a cellulose-based resin, a siloxane-based resin, apolyimide-based resin, a polyamide-based resin, or a perylene-basedresin. For example, the base layer BL may include a single-layeredpolyimide resin. However, the inventive concept is not limited thereto.For example, the base layer BL may have a laminated structure includinga plurality of insulation layers. According to another exemplaryembodiment of the inventive concept, the base layer BL may include arigid material. For example, the base layer BL may be a glass substrate.

The base layer BL may include a first area AR1 and a second area AR2adjacent to the first area AR1. The first area AR1 and the second areaAR2 may be areas that are divided when viewed on the plane. The firstarea AR1 and the second area AR2 will be described below in detail.

The pixel circuit layer PXCL is disposed on the base layer BL. The pixelcircuit layer PXCL may include a pixel circuit PXC and a plurality ofinsulation layers L1, L2, and L3. In FIG. 4, a first transistor TR1 anda second transistor TR2 of the pixel circuit PXC are illustrated.

The first transistor TR1 may include a first control electrode CE1, afirst input electrode IE1, a first output electrode OE1, and a firstsemiconductor pattern SP1. The second transistor TR2 may include asecond control electrode CE2, a second input electrode IE2, a secondoutput electrode OE2, and a second semiconductor pattern SP2.

The first control electrode CE1 and the second control electrode CE2 maybe disposed on the base layer BL. Each of the first control electrodeCE1 and the second control electrode CE2 may include a metal material.

The first insulation layer L1 may be disposed on the base layer BL tocover the first control electrode CE1 and the second control electrodeCE2. That is, the first control electrode CE1 and the second controlelectrode CE2 may be disposed between the first insulation layer L1 andthe base layer BL.

A first semiconductor pattern SP1 and a second semiconductor pattern SP2may be disposed on the first insulation layer L1. The firstsemiconductor pattern SP1 may be disposed to be spaced apart from thefirst control electrode CE1 on the cross-section, and the secondsemiconductor pattern SP2 may be disposed to be spaced apart from thesecond control electrode CE2 on the cross-section.

Each of the first and second semiconductor patterns SP1 and SP2 mayinclude a semiconductor material. For example, the first semiconductorpattern SP1 and the second semiconductor pattern SP2 may include thesame semiconductor material. Alternatively, the first semiconductorpattern SP1 and the second semiconductor pattern SP2 may includesemiconductor materials different from each other. For example, thesemiconductor material may include at least one of amorphous silicon,polycrystalline silicon, single crystal silicon, an oxide semiconductor,and a compound semiconductor.

The first input electrode IE1 and the first output electrode OE1 may bedisposed on the first semiconductor pattern SP1, and second inputelectrode IE2 and the second output electrode OE2 may be disposed on thesecond semiconductor pattern SP2.

The second insulation layer L2 may be disposed on the first insulationlayer L1 to cover the first and second semiconductor patterns SP1 andSP2, the first and second input electrodes IE1 and IE2, and the firstand second output electrodes OE1 and OE2. The first and secondsemiconductor patterns SP1 and SP2, the first and second inputelectrodes IE1 and IE2, and the first and second output electrodes OE1and OE2 may be disposed between the first insulation layer L1 and thesecond insulation layer L2.

The third insulation layer L3 may be disposed on the second insulationlayer L2. For example, each of the first insulation layer L1 and thesecond insulation layer L2 may include an inorganic material, and thethird insulation layer L3 may include an organic material. The thirdinsulation layer L3 may provide a planarization surface.

A connection electrode CCE may be disposed on the third insulation layerL3. The connection electrode CCE may connect the first output electrodeOE1 to the second control electrode CE2. A through-hole may be definedin each of the second and third insulation layers L2 and L3. The firstoutput electrode OE1 may be exposed through the through-holes. Theconnection electrode CCE may be electrically connected to the exposedfirst output electrode OE1. A through-hole may be defined in each of thefirst to third insulation layers L1, L2, and L3. The second outputelectrode OE2 may be exposed through the through-holes. The connectionelectrode CCE may be electrically connected to the exposed secondcontrol electrode CE2.

The first electrode E1 may be disposed on the third insulation layer L3.A through-hole may be defined in each of the second and third insulationlayers L2 and L3. The second output electrode OE2 may be exposed throughthe through-holes. The first electrode E1 may be electrically connectedto the second output electrode OE2.

The second electrode E2 may be disposed on the third insulation layerL3. Although not shown, the second electrode E2 may be electricallyconnected to the second power source line PL2 (see FIG. 3). That is, thesecond power source voltage ELVSS(see FIG. 3) may be provided to thesecond electrode E2.

The second electrode E2 may be spaced apart from the first electrode E1and disposed on the same layer as the first electrode E1. For example, agroove HM may be defined in the pixel circuit layer PXCL. The groove HMmay be defined by an inclined part SLP including ends of the first tothird insulation layers L1, L2, and L3.

The first electrode E1 may be disposed on the third insulation layer L3,the inclined part SLP, and the base layer BL, and the second electrodeE2 may be disposed on the third insulation layer L3, the inclined partSLP, and the base layer BL.

The connection electrode CCE, the first electrode E1, and the secondelectrode E2 may include the same conductive material. For example, eachof the connection electrode CCE, the first electrode E1, and the secondelectrode E2 may include a reflective material. Each of the connectionelectrode CCE, the first electrode E1, and the second electrode E2 mayhave a single layer structure or a multilayered structure. For example,each of the connection electrode CCE, the first electrode E1, and thesecond electrode E2 may have a structure in which indium tin oxide(ITO), silver (Ag), and indium tin oxide (ITO) are sequentiallylaminated. However, the inventive concept is not limited thereto. Forexample, each of the connection electrode CCE, the first electrode E1,and the second electrode E2 may include indium zinc oxide (IZO), indiumtin oxide (ITO), indium gallium oxide (IGO), indium zinc gallium oxide(IGZO), and a mixture/compound thereof or may include molybdenum,silver, titanium, copper, aluminum, or an alloy thereof.

The light emitting element ED may be disposed on the first electrode E1and the second electrode E2 and electrically connected to the firstelectrode E1 and the second electrode E2.

The light emitting element ED may be transferred onto the firstelectrode E1 and the second electrode E2. For example, the lightemitting element ED may be provided in plurality. Here, the plurality oflight emitting elements ED may be transferred at the same time, or eachof the plurality of light emitting elements ED may be separatelytransferred.

A method for transferring the light emitting element ED onto the firstelectrode E1 and the second electrode E2 may include a direct transfermethod and a printing transfer method. The direct transfer method may bea method for directly transferring the light emitting element ED to thefirst electrode E1 and the second electrode E2. The printing transfermethod may be a method for transferring the light emitting element ED tothe first electrode E1 and the second electrode E2 by using anelectrostatic head, a flat stamp, or a roll stamp. According to anexemplary embodiment of the inventive concept, only the first electrodeE1, the second electrode E2, and the base layer BL may be disposed belowthe area on which the light emitting element ED is disposed. Theconstituents of the pixel circuit PXC, for example, the first transistorTR1 and the second transistor TR2 may not be disposed below the lightemitting element ED.

While the light emitting element ED is transferred, a pressure may beapplied to the area on which the light emitting element ED is disposed.According to an exemplary embodiment of the inventive concept, since thepixel circuit PXC is not disposed below the light emitting element ED,the pixel circuit PXC may be prevented from being damaged by thepressure. In addition, since the light emitting element ED is disposedon the same layer as the pixel circuit PXC, the display panel DP may bereduced in thickness, thereby improving flexibility of the display panelDP.

The first area AR1 of the base layer BL may be an area overlapping thelight emitting element ED when viewed on the plane. The second area AR2may be an area overlapping a peripheral area of the area on which thelight emitting element ED is disposed when viewed on the plane. Forexample, when viewed on the plane, the second area AR2 may be defined asan area that does not overlap the light emitting element ED. That is, anemission area from which light is emitted from the display panel DP maycorrespond to the first area AR1, and the second area AR2 may correspondto a peripheral area adjacent to the emission area PXA, for example, anon-emission area NPAX.

The encapsulation layer ECL may cover the pixel circuit layer PXCL, theconnection electrode CCE, the first electrode E1, the second electrodeE2, and the light emitting element ED. The encapsulation layer ECL mayprotect the pixel circuit layer PXCL, the connection electrode CCE, thefirst electrode E1, the second electrode E2, and the light emittingelement ED against foreign substances, such as moisture/oxygen or dustparticles. The encapsulation layer ECL may be a laminated structure. Forexample, the encapsulation layer ECL may include at least one organicencapsulation layer and at least one inorganic encapsulation layer,which are alternately laminated.

According to another exemplary embodiment of the inventive concept, theencapsulation layer ECL may include only the organic encapsulationlayer. In this case, the encapsulation layer ECL may have a relativelysmall thickness when compared to the case in which the inorganicencapsulation layer is provided. Also, since the encapsulation layer ECLdoes not include the inorganic encapsulation layer that is relativelyrigid when compared to the organic encapsulation layer, the displaypanel DP may have improved flexibility.

The first refraction layer CL1 may be disposed on the encapsulationlayer ECL. The first refraction layer CL1 may have a first refractiveindex. The first refraction layer CL1 may be disposed to surround asurrounding of the light emitting element ED on the plane. The firstrefraction layer CL1 may be a layer that is patterned in a predeterminedshape. Thus, the first refraction layer CL1 may be called a firstpattern part.

The light blocking layer BM may be disposed on the encapsulation layerECL. The light blocking layer BM may have a color that absorbs light.For example, the light blocking layer BM may a black or dark gray layer.The light blocking layer BM may overlap the pixel circuit PXC on theplane. For example, the light blocking layer BM may overlap the firsttransistor TR1 and the second transistor TR2. Also, the light blockinglayer BM may overlap remaining areas except for the first area AR1. Forexample, the light blocking layer BM may overlap the second area AR2.

The light blocking layer BM may absorb external light incident into thepixel circuit PXC. That is, the light blocking layer BM may be providedto prevent the external light from being reflected by the pixel circuitPXC. The light blocking layer BM may prevent the external light frombeing reflected to improve display quality.

According to an exemplary embodiment of the inventive concept, the lightblocking layer BM and the first refraction layer CL1 may be disposed onthe same layer, for example, the encapsulation layer ECL. Also, thelight blocking layer BM and the first refraction layer CL1 may bedisposed adjacent to each other and may not overlap each other on theplane.

The second refraction layer CL2 may cover the first refraction layer CL1and the light blocking layer BM and be disposed on the first refractionlayer CL1, the light blocking layer BM, and the encapsulation layer ECL.Thus, the second refraction layer CL2 may overlap the first area AR1 andthe second area AR2 when viewed on the plane.

The first refraction layer CL1 may have a first refractive index, andthe second refraction layer CL2 may have a second refractive indexgreater than that of the first refraction layer. For example, when thefirst refractive index is about 1.5, the second refractive index may beabout 1.65. However, this is merely an example. For example, the valuesof the first refractive index and the second refractive index are notlimited to the above-described values.

The first refraction layer CL1 may include a low-refractive indexmaterial, and the second refraction layer CL2 may include ahigh-refractive index material.

According to an exemplary embodiment of the inventive concept, the firstrefraction layer CL1 may include a base material and hollow particlesthat are mixed with the base material. For example, the base materialmay include acrylic or siloxane. The hollow particles may be mixed withthe base material to reduce the refractive index. The hollow particlesmay be particles surrounded by a porous or non-porous shell, and each ofthe hollow particles may have a hollow center. Also, the firstrefraction layer CL1 may include a material that is capable of beingpatterned.

According to an exemplary embodiment of the inventive concept, thesecond refraction layer CL2 may include a material having a refractiveindex greater than that of the first refraction layer CL1. For example,the second refraction layer CL2 may include a base material and ahigh-refractive index material that is capable of improving therefractive index. For example, the base material may include acrylic orsiloxane. For example, the high-refractive index material at least oneof zirconium oxide (ZrO_(X)), titanium dioxide (TiO₂), calcium carbonate(CaCO₃), silicon dioxide (SiO₂), zinc oxide (ZnO), magnesium hydroxide(Mg(OH)₂), and lithopone (BaSO₂₊ZnS). According to another exemplaryembodiment of the inventive concept, the first refraction layer CL1 maynot include the hollow particles, and the second refraction layer CL2may not include the high-refractive index material. In this case, thefirst refraction layer CL1 may be made of a material selected frommaterials having a refractive index less than that of the secondrefraction layer CL2, and the second refraction layer CL2 may be made ofa material selected from materials having a refractive index greaterthan that of the first refraction layer CL1.

Light LGT emitted from the light emitting element ED may be incidentinto the first refraction layer CL1. Since the refractive indexes of thefirst refraction layer CL1 and the second refraction layer CL2 aredifferent from each other, the light LGT may be totally reflected orrefracted by a boundary between the first refraction layer CL1 and thesecond refraction layer CL2 so as to change its optical path. The lightLGT that is changed in optical path may be emitted to the emission areaPXA. Thus, the display panel DP may be improved in emission efficiency.

FIG. 5 is an enlarged plan view illustrating a portion of constituentsof the display device according to an exemplary embodiment of theinventive concept.

Referring to FIG. 5, the light emitting element ED is disposed on thearea overlapping the first area AR1, and the first refraction layer CL1and the light blocking layer BM are disposed on the area overlapping thesecond area AR2 (see FIG. 4). The first refraction layer CL1 may have ashape that surrounds the surrounding of the light emitting element ED.

When viewed on the plane, the first refraction layer CL1 may have ashape that surrounds the first area AR1. Although the first refractionlayer CL1 has a rectangular ring shape in FIG. 5, the inventive conceptis not limited thereto. The first refraction layer CL1 may be deformedin shape to correspond to that of the first area AR1, deformed in shapeto correspond to that of the emission area PXA (see FIG. 4), or deformedin shape to correspond to that of the light emitting element ED. Forexample, when the light emitting element ED has a circular shape on theplane, the first refraction layer CL1 may have a circular ring shape.

Light, which is incident into the first refraction layer CL1, of thelight emitted from the light emitting element ED may be totallyreflected or refracted to emit light through the area overlapping thelight emitting element ED. Thus, emission efficiency of the displaydevice DD (see FIG. 1) may be improved.

FIG. 6A is an enlarged plan view illustrating a portion of theconstituents of the display device according to an exemplary embodimentof the inventive concept.

Referring to FIG. 6A, one pixel PX (see FIG. 3) may include a pluralityof light emitting elements EDa and EDb. The light emitting elements EDaand EDb may include a first light emitting element EDa and a secondlight emitting element EDb. The first light emitting element EDa and thesecond light emitting element EDb may be connected in parallel to eachother. The first light emitting element EDa and the second lightemitting element EDb may be electrically connected to the firstelectrode E1 and the second electrode E2, respectively. The first lightemitting element EDa and the second light emitting element EDb may bedisposed to overlap the first area AR1.

The first refraction layer CL1 a may have a ring shape on the plane tosurround the first and second light emitting elements EDa and EDb. Thefirst and second light emitting elements EDa and EDb may light emittingelements provided in one pixel. Thus, an area between the first lightemitting element EDa and the second light emitting element EDb maycorrespond to the emission area PXA of FIG. 4. Thus, a first refractionlayer CL1 a may not be disposed between the first light emitting elementEDa and the second light emitting element EDb.

FIG. 6B is an enlarged plan view illustrating a portion of theconstituents of the display device according to an exemplary embodimentof the inventive concept. In the description of FIG. 6B, contentsdifferent from those of FIG. 6A will be described.

Referring to FIG. 6B, a first refraction layer CL1 b may surround eachof the first and second light emitting elements EDa and EDb on theplane. Thus, the first refraction layer CL1 b may be disposed on an areabetween the first light emitting element EDa and the second lightemitting element EDb.

In FIGS. 5, 6A and 6B, the first refraction layers CL1, CL1 a, and CL1 bare shaded to clearly distinguish the first refraction layers CL1, CL1a, and CL1 b from each other.

FIG. 7A is an enlarged cross-sectional view illustrating a portion ofthe display device according to an exemplary embodiment of the inventiveconcept. In FIG. 7A, the encapsulation layer ECL, the first refractionlayer CL1, the second refraction layer CL2, and the light blocking layerBM are illustrated.

Referring to FIG. 7A, the first refraction layer CL1 may have atrapezoidal shape in cross-section. Thus, a boundary surface between thefirst refraction layer CL1 and the second refraction layer CL2 may havea shape that is inclined with respect to the outermost surface of theencapsulation layer ECL. Light incident into the boundary surface fromthe second refraction layer CL2 toward the first refraction layer CL1may have an incident angle greater than that when the boundary surfaceis perpendicular to the encapsulation layer ECL. Thus, the probabilitythat the light incident into the boundary surface is totally reflectedmay increase. As a result, the probability that the light incident intothe first refraction layer CL1 is totally reflected or refracted to beemitted to the emission area PXA (see FIG. 4) may increase. That is, thedisplay device DD (see FIG. 1) may be improved in light extractionefficiency.

FIG. 7B is an enlarged cross-sectional view illustrating a portion ofthe display device according to an exemplary embodiment of the inventiveconcept.

Referring to FIG. 7B, a first refraction layer CL1-1 may include aplurality of cover patterns CLPt. The cover patterns CLPt may bedisposed to be spaced apart from each other. The first refraction layerCL1-1 includes three cover patterns CLPt, but the inventive concept isnot limited thereto. The number of cover patterns CLPt may be two,three, or more than three.

Each of the cover patterns CLPt may have a rectangular shape on thecross-section. However, the inventive concept is not limited thereto.For example, each of the cover patterns CLPt may have a trapezoidalshape in cross-section, and the outermost surface of the each of thecover patterns CLPt may have a curved shape.

FIG. 7C is an enlarged cross-sectional view illustrating a portion ofthe display device according to an exemplary embodiment of the inventiveconcept.

Referring to FIG. 7C, the outermost surface of a first refraction layerCL1-2 may have a curved shape. For example, the first refraction layerCL1-2 may have a semicircular shape that is convex in the cross-section.Thus, a boundary surface between the first refraction layer CL1 and thesecond refraction layer CL2 may have an inclined shape. Light incidentinto the boundary surface may have an incident angle greater than thatwhen the boundary surface is perpendicular to the encapsulation layerECL. Thus, the probability that the light incident into the boundarysurface is totally reflected may increase. As a result, the probabilitythat the light incident into the first refraction layer CL1-2 is totallyreflected or refracted to be emitted to the emission area PXA (see FIG.4) may increase. That is, light extraction efficiency of the displaydevice DD (see FIG. 1) may be improved.

FIG. 7D is an enlarged cross-sectional view illustrating a portion ofthe display device according to an exemplary embodiment of the inventiveconcept.

Referring to FIG. 7D, the outermost surface of a first refraction layerCL1-3 contacting the second refraction layer CL2 has a curved shape. Forexample, the first refraction layer CL1-3 may have a shape in which aconvex area and a concave area are alternately repeated. Since the firstrefraction layer CL1-3 has the curved shape, although light incidentfrom the outside is reflected by a metal disposed below the firstrefraction layer CL1-3, for example, the first electrode E1 (see FIG.4), the reflected light may be scattered on a top surface of the firstrefraction layer CL1-3. Thus, the phenomenon in which the light incidentfrom the outside is reflected to be emitted again to the outside of thedisplay panel DP (see FIG. 4) may be prevented.

FIG. 8 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept. In description of FIG. 8,the same reference numeral may be given to components that are the sameas the components of FIG. 4, and their detailed descriptions will beomitted.

Referring to FIG. 8, a light blocking layer BM of a display panel DP-1may be disposed on the encapsulation layer ECL. The light blocking layerBM may be disposed on the second area AR2 to cover the first transistorTR1 and the second transistor TR2.

A first refraction layer CL1-4 may be disposed on the light blockinglayer BM and the encapsulation layer ECL. The first refraction layerCL1-4 may be disposed on the second area AR2 to cover the light blockinglayer BM.

The second refraction layer CL2 may be disposed on the first refractionlayer CL1-4 to cover the first refraction layer CL1-4. The secondrefraction layer CL2 may provide a planarization surface.

The first refraction layer CL1-4 may include a material having a firstrefractive index, and the second refraction layer CL2 may include amaterial having a second refractive index greater than the firstrefractive index.

FIG. 9 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept. In description of FIG. 9,the same reference numeral may be given to components that are the sameas the components of FIG. 4, and their detailed descriptions will beomitted.

Referring to FIG. 9, a light blocking layer BMa of a display panel DP-2may be disposed below the encapsulation layer ECL. Also, the lightblocking layer BMa may be disposed between the third insulation layer L3and the encapsulation layer ECL. The light blocking layer BMa maydirectly cover the connection electrode CCE, a portion of the firstelectrode E1, and a portion of the second electrode E2. The term“directly cover” may mean that the light blocking layer BMa and theconnection electrode CCE are directly disposed with respect to eachother without providing another constituent between the light blockinglayer BMa and the connection electrode CCE.

The light blocking layer BMa may absorb light incident from the outsideto prevent the light from being reflected by the connection electrodeCCE, the first electrode E1, and the second electrode E2.

FIG. 10 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept. In description of FIG.10, the same reference numeral may be given to components that are thesame as the components of FIG. 4, and their detailed descriptions willbe omitted.

Referring to FIG. 10, a second refraction layer CL2-1 of a display panelDP-3 may cover the light emitting element ED. Thus, when viewed on theplane, the second refraction layer CL2-1 may overlap the first area AR1.

The second refraction layer CL2-1 may include a material having a secondrefractive index. The material having the second refractive index may bea material having a refractive index greater than a first refractiveindex of a first refraction layer CL1-5.

The second refraction layer CL2-1 may include a base material such asacrylic or siloxane and a high-refractive index material mixed with thebase material. For example, the high-refractive index material at leastone of zirconium oxide (ZrO_(X)), titanium dioxide (TiO₂), calciumcarbonate (CaCO₃), silicon dioxide (SiO₂), zinc oxide (ZnO), magnesiumhydroxide (Mg(OH)₂), and lithopone (BaSO₂₊ZnS). However, the inventiveconcept is not limited thereto. For example, the high-refractive indexmaterial is not limited to a specific material as long as the secondrefraction layer CL2-1 includes a material having a refractive indexgreater than that of the first refraction layer CL1-5.

The second refraction layer CL2-1 may be provided to the light emittingelement ED through an inkjet process, but the process of forming thesecond refraction layer CL2-1 is not limited thereto.

The second refraction layer CL2-1 may have a lens shape. That is, thesecond refraction layer CL2-1 may have a curved outermost surface. Thesecond refraction layer CL2-1 may be called a pattern layer.

The light blocking layer BMa may be disposed on the third insulationlayer L3. The light blocking layer BMa may cover the connectionelectrode CCE, a portion of the first electrode E1, and a portion of thesecond electrode E2.

The first refraction layer CL1-5 may be disposed on the secondrefraction layer CL2-1 and the light blocking layer BMa. The firstrefraction layer CL1-5 may provide a planarization surface at theoutermost surface. The first refraction layer CL1-5 may include amaterial having a first refractive index. The first refractive index maybe smaller than the second refractive index. For example, the firstrefraction layer CL1-5 may include a base material and hollow particlesthat are mixed with the base material.

Light LGTa emitted from the light emitting element ED may be refractedby a boundary surface between the first refraction layer CL1-5 and thesecond refraction layer CL2-1. Since the first refraction layer CL1-5has the refractive index less than that of the second refraction layerCL2-1, collection of the light LGTa may increase. Thus, light extractionefficiency of the display panel DP-3 may be improved.

FIG. 11 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept. In description of FIG.11, the same reference numeral may be given to components that are thesame as the components of FIG. 4, and their detailed descriptions willbe omitted.

Referring to FIG. 11, a display panel DP-4 may further include a colorfilter layer CF. The color filter layer CF may be provided to reducereflection of external light. The color filter layer CF may reduce thereflection of the external light to improve display quality. Accordingto an exemplary embodiment of the inventive concept, the display panelDP-4 may include the color filter layer CF and may not include apolarizing member. Thus, the reflection of the external light may bereduced while minimizing reduction of luminance to improve the displayquality.

The light blocking layer BM and the color filter layer CF may bedisposed on the encapsulation layer ECL. A planarization layer PLL maybe disposed on the encapsulation layer ECL. The planarization layer PLLmay cover the light blocking layer BM and the color filter layer CF andprovide a planarization surface.

The light blocking layer BM may overlap the second area AR2 on the planeand be disposed between the encapsulation layer ECL and the polarizationlayer PLL. The color filter layer CF may overlap the first area AR1 onthe plane and be disposed between the encapsulation layer ECL and thepolarization layer PLL.

The first refraction layer CL1-6 and the second refraction layer CL2-2may be disposed on the planarization layer PLL. The first refractionlayer CL1-6 may include a material having a first refractive index, andthe second refraction layer CL2-2 may include a material having a secondrefractive index greater than that of the first refraction layer.

The first refraction layer CL1-6 may overlap the second area AR2 on theplane, and the second refraction layer CL2-2 may overlap the first areaAR1 and the second area AR2 on the plane. The second refraction layerCL2-2 may provide a planarization surface at the outermost surface ofthe display panel DP-4.

FIG. 12 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept. In description of FIG.12, the same reference numeral may be given to components that are thesame as the components of FIG. 4, and their detailed descriptions willbe omitted.

Referring to FIG. 12, a first refraction layer CL1-7 may be disposed onthe encapsulation layer ECL, and the first refraction layer CL1-7 maynot overlap the first area AR1. A second refraction layer CL2-3 maycover the first refraction layer CL1-7. The first refraction layer CL1-7may have a refractive index less than that of the second refractionlayer CL2-3. Light incident into the first refraction layer CL1-7 may betotally reflected by a boundary between the first refraction layer CL1-7and the second refraction layer CL2-3 and then be emitted to theemission area PXA.

A display panel DP-5 may further include a color filter layer CF-1. Alight blocking layer BMb and the color filter layer CF-1 may be disposedon the second refraction layer CL2-3. The light blocking layer BMb mayoverlap the first and second transistors TR1 and TR2, and the colorfilter layer CF-1 may overlap the light emitting element ED on theplane.

FIG. 13 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept. In description of FIG.13, only differences from FIG. 12 will be described, and description ofthe remaining components will be omitted.

Referring to FIG. 13, a display panel DP-6 may further include a colorfilter layer CF-2 and a planarization layer PLL-1.

The color filter layer CF-2 is disposed between a thin filmencapsulation layer ECL and a second refraction layer CL2-3. That is,the second refraction layer CL2-3 may cover all the color filter layerCF-2 and the first refraction layer CL1-7.

The light blocking layer BMb may be disposed on the second refractionlayer CL2-3, and a planarization layer PLL-1 covering the light blockinglayer BMb and providing a planarization surface may be disposed on thesecond refraction layer CL2-3.

FIG. 14 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept. In description of FIG.14, the same reference numeral may be given to components that are thesame as the components of FIG. 11, and their detailed descriptions willbe omitted.

When compared to the display panel DP-4 of FIG. 11, a display panel DP-7of FIG. 14 may further include a pattern layer PTL.

The pattern layer PTL is disposed below an encapsulation layer ECLa. Thepattern layer PTL may overlap the first area AR1 and the light emittingelement ED on the plane and cover the light emitting element ED. Thepattern layer PTL may have a convex lens shape on the cross-section. Thepattern layer PTL may have a refractive index larger than that of theencapsulation layer ECLa. Thus, light emitted from the light emittingelement ED and incident into the encapsulation layer ECLa through thepattern layer PTL may be collected.

The pattern layer PTL may include a base material and a high-refractiveindex material that is capable of improving the refractive index. Forexample, the base material may include acrylic or siloxane. For example,the high-refractive index material at least one of zirconium oxide(ZrO_(X)), titanium dioxide (TiO₂), calcium carbonate (CaCO₃), silicondioxide (SiO₂), zinc oxide (ZnO), magnesium hydroxide (Mg(OH)₂), andlithopone (BaSO₂₊ZnS). The light emitted from the light emitting elementED may be primarily collected to a boundary between the pattern layerPTL and the encapsulation layer ECLa and then secondarily collected bybeing totally reflected or refracted by the boundary between a the firstrefraction layer CL1-6 and a second refraction layer CL2-2, which aredisposed on a planarization layer PLL. Thus, emission efficiency of thedisplay panel DP-7 may be improved.

FIGS. 15 and 16 are partial cross-sectional views of a display panelaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 15, a display panel DP-8 may have a configuration inwhich the display panel DP-5 of FIG. 12 and the display panel DP-7 ofFIG. 14 are combined with each other. For example, a first portion PT1of FIG. 15 may be the same as a portion of the constituents of thedisplay panel DP-7 of FIG. 14, and a second portion PT2 of FIG. 15 maybe the same as a portion of the constituents of the display panel DP-5of FIG. 12.

Referring to FIG. 16, a display panel DP-9 may have a configuration inwhich the display panel DP-6 of FIG. 13 and the display panel DP-7 ofFIG. 14 are combined with each other. For example, a first portion PT1 aof FIG. 16 may be the same constituent as the display panel DP-7 of FIG.14, and a second portion PT2 a of FIG. 16 may be the same constituent asthe display panel DP-6 of FIG. 13.

The display panel may have various combinations in addition to thecombination of the display panels of FIGS. 15 and 16. For example, thesecond portions PT2 and PT2 a may be replaced by the constituents of thedisplay panel DP of FIG. 4 and the display panel DP-1 of FIG. 8.

FIG. 17 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept. In FIG. 17, thedifferences from the constituents of FIG. 10 will be described. The samereference numerals are used for the same constituent, and a descriptionthereof will be omitted.

When compared to the display panel DP-3 of FIG. 10, a display panelDP-10 of FIG. 17 may further include a color filter layer CF-3 and aplanarization layer PLL-2.

The color filter layer CF-3 may be disposed on a first refraction layerCL1-5 and disposed to overlap the first area AR1 and the light emittingelement ED on the plane. The planarization layer PLL-2 may be disposedon the first refraction layer CL1-5 to cover the color filter layerCF-3.

FIG. 18 is a cross-sectional view of a display panel according to anexemplary embodiment of the inventive concept.

A display panel DP-11 of FIG. 18 may have the same structure as that ofthe display panel DP-7 of FIG. 14 in which the first refraction layerCL1-6 and the second refraction layer CL2-2 are omitted. A pattern layerPTL covering the light emitting element ED may have substantially thesame constituent as the second refraction layer CL2-1 of FIG. 10. Sincethe first refraction layer CL1-6 and the second refraction layer CL2-2are omitted, display panel DP-11 may be made thinner.

The pattern layer PTL of FIG. 18 may be called a second refractionlayer, and an encapsulation layer ECLa may be called a first refractionlayer. The pattern layer PTL may be substantially the same as the secondrefraction layer CL2-1 of FIG. 10, and the encapsulation layer ECLa maybe substantially the same as the first refraction layer CL1-5 of FIG.10.

FIG. 19 is an enlarged cross-sectional view illustrating a portion ofthe display device according to an exemplary embodiment of the inventiveconcept.

Referring to FIG. 19, a groove HM-1 may be defined in the pixel circuitlayer PXCL. The groove HM-1 may be defined by an inclined part SLPincluding ends of the first to third insulation layers L1, L2, and L3.

An inclined part SLP defined at one side with respect to the lightemitting element ED may be covered by a first electrode E1 a, and aninclined part SLP defined at the other side may be covered by a secondelectrode E2 b.

Each of the first electrode E1 a and the second electrode E2 b may havea multilayered structure. The first electrode E1 a may include a firstelectrode layer E1 x, a second electrode layer E1 y, and a thirdelectrode layer E1 z, which are sequentially laminated, and the secondelectrode E2 b may include a first electrode layer E2 x, a secondelectrode layer E2 y, and a third electrode layer E2 z, which aresequentially laminated.

Each of the first electrode layer Ex, the third electrode layer Ez, thefirst electrode layer E2 x, and the third electrode layer E2 z mayinclude indium tin oxide (ITO), and the second electrode layer E1 y andthe second electrode layer E2 y may include a reflective material, forexample, silver (Ag). Thus, light emitted from the light emittingelement ED may be reflected by the first electrode E1 a and the secondelectrode E2 b.

In an exemplary embodiment of the inventive concept, the groove HM-1 mayhave a depth DET greater than a thickness HIT of the light emittingelement ED. A thickness TKN of the third insulation layer L3 may beadjusted according to the thickness of the light emitting element ED toadjust the depth DET of the groove HM-1. The light emitting element EDmay be completely accommodated in the groove HM-1. Thus, light providedfrom the light emitting element ED may be reflected by the firstelectrode E1 a and the second electrode E2 b. Thus, emission efficiencyof the display panel DP (see FIG. 4) may be improved.

In another exemplary embodiment of the inventive concept, light emittedfrom the light emitting element ED may be reflected by the firstelectrode E1 a and the second electrode E2 b to sufficiently control thelight path. Thus, the first refraction layers and the second refractionlayers, which are described above, may be omitted. In addition, inanother exemplary embodiment of the inventive concept, the lightblocking layer may not be disposed on the substrate on which the lightemitting element ED is disposed, but may instead be disposed on adifferent substrate. For example, the light blocking layer may bedisposed on an opposite substrate facing the light emitting element ED.In this case, the opposite substrate may be a rigid substrate, forexample, a glass substrate.

According to the inventive concept, the display device may include thefirst refraction layer having the first refractive index and the secondrefraction layer having the second refractive index larger than thefirst refractive index. The light emitted from the light emittingelement of the display device may be refracted or totally reflected bythe boundary between the first refraction layer and the secondrefraction layer to change the light path. The emission efficiency ofthe display device may be improved by the changed light path.

Although certain exemplary embodiments have been described herein, otherembodiments and modifications will be apparent from this description.Accordingly, the inventive concepts are not limited to such embodiments,but rather to the broader scope of the appended claims and variousobvious modifications and equivalent arrangements as would be apparentto a person of ordinary skill in the art.

What is claimed is:
 1. A display device comprising: a base layercomprising a first area and a second area adjacent to the first area; apixel circuit layer disposed on the base layer and comprising a pixelcircuit and a plurality of insulation layers; a first electrodeelectrically connected to the pixel circuit; a second electrode spacedapart from the first electrode and disposed on the same layer as thefirst electrode; a light emitting element electrically connected to thefirst electrode and the second electrode; a first refraction layerdisposed on the pixel circuit layer and having a first refractive index;and a second refraction layer disposed on the light emitting element andhaving a second refractive index larger than the first refractive index,wherein the first area overlaps the light emitting element and thesecond refraction layer, and the second area overlaps the firstrefraction layer.
 2. The display device of claim 1, wherein the lightemitting element comprises a micro light emitting diode element.
 3. Thedisplay device of claim 1, further comprising an encapsulation layercovering the light emitting element and the pixel circuit.
 4. Thedisplay device of claim 3, wherein: the first refraction layer and thesecond refraction layer are disposed on the encapsulation layer; thefirst refraction layer is disposed to surround the first area on aplane; and the second refraction layer overlaps the first area and thesecond area.
 5. The display device of claim 3, further comprising alight blocking layer disposed on the encapsulation layer to overlap thepixel circuit.
 6. The display device of claim 5, wherein the lightblocking layer and the first refraction layer are disposed adjacent toeach other and covered by the second refraction layer.
 7. The displaydevice of claim 5, wherein the first refraction layer is disposed on thelight blocking layer to cover the light blocking layer.
 8. The displaydevice of claim 4, further comprising a color filter layer overlappingthe first area and disposed between the encapsulation layer and thesecond refraction layer.
 9. The display device of claim 8, furthercomprising: a light blocking layer disposed on the second refractionlayer to overlap the pixel circuit; and a planarization layer disposedon the second refraction layer to cover the light blocking layer andprovide a planarization surface.
 10. The display device of claim 4,further comprising: a light blocking layer disposed on the secondrefraction layer to overlap the pixel circuit; and a color filter layerdisposed on the second refraction layer and overlapping the first area.11. The display device of claim 4, further comprising a pattern layerdisposed below the encapsulation layer, the pattern layer covering thelight emitting element and having a third refractive index, wherein theencapsulation layer has a fourth refractive index smaller than the thirdrefractive index.
 12. The display device of claim 11, furthercomprising: a light blocking layer disposed on the second refractionlayer to overlap the pixel circuit; and a color filter disposed on thesecond refraction layer to overlap the light emitting element.
 13. Thedisplay device of claim 11, further comprising: a color filter disposedbetween the encapsulation layer and the second refraction layer tooverlap the light emitting element; a light blocking layer disposed onthe second refraction layer to overlap the pixel circuit; and aplanarization layer configured to cover the light blocking layer andprovide a planarization surface.
 14. The display device of claim 11,further comprising: a light blocking layer disposed on the encapsulationlayer to overlap the pixel circuit; a color filter layer disposed on theencapsulation layer to overlap the light emitting element; and aplanarization layer configured to cover the light blocking layer and thecolor filter layer, wherein the first refraction layer and the secondrefraction layer are disposed on the planarization layer.
 15. Thedisplay device of claim 1, wherein: the second refraction layer coversthe light emitting element; and the first refraction layer is disposedon the second refraction layer and the pixel circuit layer to cover thesecond refraction layer.
 16. The display device of claim 15, wherein anoutermost surface of the second refraction layer contacts the firstrefraction layer and has a predetermined curvature.
 17. The displaydevice of claim 15, further comprising a light blocking layer, whichdoes not overlap the light emitting element, wherein the light blockinglayer is disposed between the first refraction layer and the pixelcircuit layer.
 18. The display device of claim 17, further comprising: acolor filter layer disposed on the first refraction layer to overlap thelight emitting element; and a planarization layer disposed on the firstrefraction layer to cover the color filter layer.
 19. The display deviceof claim 15, further comprising: a light blocking layer which does notoverlap the light emitting element and is disposed on the firstrefraction layer; a color filter layer disposed on the first refractionlayer to overlap the light emitting element; and a planarization layerdisposed on the first refraction layer to cover the color filter layer.20. The display device of claim 1, wherein: a groove is defined in thepixel circuit layer by an inclined part comprising an end of each of theplurality of insulation layers; and the light emitting element isdisposed in the groove.
 21. The display device of claim 20, wherein: theinclined part is covered by the first electrode and the secondelectrode; and each of the first electrode and the second electrodecomprises a reflective material.
 22. The display device of claim 20,wherein the groove has a depth greater than a thickness of the lightemitting element.
 23. A display device comprising: a base layer; a pixelcircuit layer disposed on the base layer and comprising a transistor andinsulation layers, each of the insulation layers having a groove; afirst electrode electrically connected to the transistor; a secondelectrode spaced apart from the first electrode and configured toreceive a power source voltage; a light emitting element electricallyconnected to the first electrode and the second electrode and disposedin the groove; a first refraction layer overlapping an area adjacent toan emission area on which the light emitting element is disposed andhaving a first refractive index; and a second refraction layeroverlapping the emission area and having a second refractive indexlarger than the first refractive index.
 24. The display device of claim23, wherein: the first refraction layer is disposed on the pixel circuitlayer; and the second refraction layer is disposed on the firstrefraction layer to cover the first refraction layer and provide aplanarization surface.
 25. The display device of claim 23, wherein: thesecond refraction layer is disposed on the light emitting element; andthe first refraction layer is disposed on the second refraction layer tocover the second refraction layer and provide a planarization surface.26. The display device of claim 23, wherein: the groove is defined by aninclined part comprising an end of each of the insulation layers; thefirst electrode covers one portion of the inclined part; the secondelectrode covers the other portion of the inclined part; and each of thefirst electrode and the second electrode comprises a reflectivematerial.
 27. The display device of claim 23, wherein the groove has adepth greater than a thickness of the light emitting element.